A white supremacist who killed a security guard at a Holocaust memorial museum in the US has links to the British National party, which gained two MEPs in last week's European elections.

Thousands of visitors fled the museum in Washington on Wednesday after James von Brunn opened fire, killing a security guard. In the gunfight that followed, the 88-year-old was shot, and is now in a critical condition in hospital.

Yesterday it emerged that Von Brunn, a longtime antisemite, had attended meetings of the American Friends of the British National party (AFBNP), which was set up to raise funds from far-right activists in America.

Mark Cotterill, who ran the US-based organisation before it folded in 2001, said: "He did attend meetings. I have just checked my database and he is down as 'meetings only', so he was not a major donor, although he may have put some money on the plate when it was passed round."

The AFBNP treasurer, Todd Blodgett, also told the Washington Post that he and Von Brunn had attended fundraising meetings in Arlington County. The BNP leader, Nick Griffin, spoke to at least two AFBNP meetings and said the money raised by the organisation made a "significant contribution to the BNP's [2001] general election campaign".

Yesterday a spokesman for the party said: "You get a lot of people coming to meetings but I don't think you can blame us for that. Even if he did go to meetings, it was nothing to do with us."

However, anti-racism campaigners said Von Brunn's links to the BNP underlined its extremist agenda. "It is clear that Nick Griffin is at the centre of an international network of white supremacists," said Dan Hodges, of Searchlight. "The BNP must explain the full extent of his organisation's links with this antisemitic gunman."

The far-right party gained its first two MEPs in last week's European elections – Griffin in the north-west and former National Front leader Andrew Brons in Yorkshire and the Humber.

During the campaign, photographs emerged of Griffin alongside the former Ku Klux Klan grand wizard Stephen "Don" Black, who was banned from the UK by the then home secretary, Jacqui Smith. He was also criticised for defending a BNP leaflet that said black and Asian Britons should be referred to as "racial foreigners".

Yesterday Von Brunn was charged with murder and killing in the course of possessing a firearm at a federal facility, both capital offences under US federal law; police said hate crime charges were also possible.

At a press conference in Washington, Cathy Lanier, the Washington police chief, said security guard Stephen Johns was shot when he opened the door of the museum for Von Brunn. Other guards opened fire, and Von Brunn slumped to the ground.

In his car, officers found a notebook with a handwritten note saying, "You want my weapons, this is how you'll get them. The Holocaust is a lie. Obama was created by Jews," according to a court affidavit.

Von Brunn's .22-calibre rifle held 10 more bullets and investigators found more in his car and at an apartment in nearby Annapolis, Maryland, that he shared with his son and his son's fiancee.

Joseph Persichini, assistant director of the Washington FBI field office, said Von Brunn was known to the police as an antisemite and a white supremacist, who had a website that espoused hatred against African-Americans, Jews and others.

"We know what Mr Von Brunn did at the Holocaust museum. Now it's our responsibility to determine why he did it," said Joseph Persichini, assistant director of the Washington FBI field office. "We have to ask ourselves did all these years of public display of hatred impact his actions."

A self-described artist, advertising man and author, Von Brunn wrote an anti-semitic treatise, Kill the Best Gentiles, decried "the browning of America" and claimed to expose a Jewish conspiracy "to destroy the White gene-pool".

In 1983 Von Brunn was convicted of attempting to kidnap members of the US federal reserve board. At the time, police said he had wanted to take the members hostage because of high interest rates and the nation's economic difficulties. On the website, Von Brunn blames his six-year imprisonment on "a Jew judge" and "Negro jury".

Last night civil rights groups said they had been monitoring Von Brunn for decades.

Heidi Beirich, director of research for the Southern Poverty Law Centre's intelligence project, said: "He thinks the Jews control the Federal Reserve, the banking system, that basically all Jews are evil. He's an extreme antisemite."